One of the most diverse congress in US history: 80% white,80% male,92% Christian (washingtonpost.com)

To contrast: http://en.wikipedia.org/wiki/Demographics_of_the_United_Stat...

So from this I get that there is ~60% (0.83*0.72) of non-hispanic whites in the population. Is that about right?

Comprising 20 percent of the public and 0.2 percent of Congress, it seems atheists are the least proportional represented group of all minorities.